Medium 16x16 Sudoku turns a coffee break into an evening. Singles carry the opening, then pairs and box-line reductions take over across 256 cells. Nothing here is exotic — the challenge is stamina and keeping sixteen symbols straight in your notes.
Rated 2.0–2.9 by Sudoku Explainer, medium giant grids are the default when you open the 16x16 mode fresh. Your progress is saved after every move, so a puzzle can span several sessions. Prefer a quicker game? Switch to medium 9x9 Sudoku.